<?php
/*
 *  $Id: Email.php 7490 2010-03-29 19:53:27Z jwage $
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * This software consists of voluntary contributions made by many individuals
 * and is licensed under the LGPL. For more information, see
 * <http://www.doctrine-project.org>.
 */

/**
 * Doctrine_Validator_Email
 *
 * @package     Doctrine
 * @subpackage  Validator
 * @license     http://www.opensource.org/licenses/lgpl-license.php LGPL
 * @link        www.doctrine-project.org
 * @since       1.0
 * @version     $Revision: 7490 $
 * @author      Konsta Vesterinen <kvesteri@cc.hut.fi>
 */
class Doctrine_Validator_Email extends Doctrine_Validator_Driver
{
	/**
	 * checks if given value is a valid email address
	 *
	 * @link http://iamcal.com/publish/articles/php/parsing_email/pdf/
	 * @param mixed $value
	 * @return boolean
	 */
	public function validate($value)
	{
		if (is_null($value)) {
			return true;
		}

		if (isset($this->args) && (! isset($this->args['check_mx']) || $this->args['check_mx'] == true)) {
			$parts = explode('@', $value);

			if (isset($parts[1]) && $parts[1] && ! $this->_checkMX($parts[1])) {
				return false;
			}
		}

		$e = explode('.', $value);
		$tld = end($e);

		if (preg_match("/[^a-zA-Z]/", $tld)) {
			return false;
		}

		$qtext = '[^\\x0d\\x22\\x5c\\x80-\\xff]';
		$dtext = '[^\\x0d\\x5b-\\x5d\\x80-\\xff]';
		$atom = '[^\\x00-\\x20\\x22\\x28\\x29\\x2c\\x2e\\x3a-\\x3c\\x3e\\x40\\x5b-\\x5d\\x7f-\\xff]+';
		$quotedPair = '\\x5c[\\x00-\\x7f]';
		$domainLiteral = "\\x5b($dtext|$quotedPair)*\\x5d";
		$quotedString = "\\x22($qtext|$quotedPair)*\\x22";
		$domainRef = $atom;
		$subDomain = "($domainRef|$domainLiteral)";
		$word = "($atom|$quotedString)";
		$domain = "$subDomain(\\x2e$subDomain)+";

		/*
		 following pseudocode to allow strict checking - ask pookey about this if you're puzzled

		 if ($this->getValidationOption('strict_checking') == true) {
		 $domain = "$sub_domain(\\x2e$sub_domain)*";
		 }
		 */

		$localPart = "$word(\\x2e$word)*";
		$addrSpec = "$localPart\\x40$domain";

		return (bool) preg_match("!^$addrSpec$!D", $value);
	}

	/**
	 * Check DNS Records for MX type
	 *
	 * @param string $host Host name
	 * @return boolean
	 */
	private function _checkMX($host)
	{
		// We have different behavior here depending of OS and PHP version
		if (strtolower(substr(PHP_OS, 0, 3)) == 'win' && version_compare(PHP_VERSION, '5.3.0', '<')) {
			$output = array();

			@exec('nslookup -type=MX '.escapeshellcmd($host) . ' 2>&1', $output);

			if (empty($output)) {
				throw new Doctrine_Exception('Unable to execute DNS lookup. Are you sure PHP can call exec()?');
			}

			foreach ($output as $line) {
				if (preg_match('/^'.$host.'/', $line)) {
					return true;
				}
			}

			return false;
		} else if (function_exists('checkdnsrr')) {
			return checkdnsrr($host, 'MX');
		}

		throw new Doctrine_Exception('Could not retrieve DNS record information. Remove check_mx = true to prevent this warning');
	}
}